I took some shots with my 5x7 of the navy ships arriving in New York for "Fleet Week". It was a drizzly, foggy day, to the point where the NYC skyline was often invisible from across the Hudson in New Jersey.
Spotmeter readings indicated less than 2 stop range from dark to light. I shot tri-x rated at 320. Mixed the pyrocat at 20ml each of A and B to 1 liter of water. Developed first set of sheets in a Jobo at 12min @68. VERY thin negs. second set of negs were developed at 24 min to try to get more expansion. these negs look only slightly better than the first set.
is pryocat a bad choice for expansion? would I have been better off using D76 or HC110?
some of the shots have pretty good content. in terms of intensification would I be better off trying to salvage them with selenium or chromium intensifier?
thanks for any help.
Something is way off with your procedure. Pyrocat-HD is an excellent developer for expansion. 24 minutes of development at the 2:2:100 mixture with TRI-X should give you negatives that would be so contrasty they would be unprintable with silver printing. The CI would be well over 1.0, even with the very flat circumstances you describe.
For example, some recent tests I did show the following CI (contrast index) for Pyrocat 2:2:100 and TRI-X film, with develoment in tubes at 70F.
Development Time Contrast Index
6 minutes .55
8 minutes .65
10 minutes .80
14 minutes .90
20 minutes .98
Since a CI of just slightly over .50 would be considered normal for silver gelatin printing you can see how much room for expansion there would be Pyrocat-HD and the 2:2:100 dilution.
Based on your description of very thin negatives I suspect that you did not give enough expoosure, or your negatives suffered from reciprocity failure. There is simply no way in the world a properely exposed negative developed for 24 minutes in Pyrocat-HD could be thin. In fact, it would be so dense and contrasty it would be difficult to make a good print with it even with a process like salted paper that requires an extremely contrasty negative.
Of course there is always the possibililty that there is something wrong with your stock solutions, or that the working solution was not mixed correctly.
Regarding your question of chromium or selenium intensification:
The tests which are shown in the back of A A book "The Negative" , indicate that selenium intensification gives a .40 density increase to a 1.50 beginning density. The intensification continues in a more fairly straight line and seems to exhibit a truly proportional increase to the density of the negative.
The test which is shown for IN-4 intensification (Chromium) show that with a 1.50 beginning density that a .40 density is also obtained. However the curve of this means of intensification indicates tha a fairly pronounced shoulder is inherent. This method gives more early increase in density and does not exhibit truly proportional tendencies.
In summary the curves indicate that when a means of increasing contrast in a negative is desired that selenium is the more effective. Provided of course that sufficient density is present on the negative.
I agree with Sandy, Pyrocat HD is a very versatile formula but you have to do some testing. I use KOH 10%as the activator ( is all I got, hard to get stuff here in Mx) and if I use the usual 1:2:100 formula I get negatives that are hard to print even on pt/pd. My usual ratio is 1:1.5:100, and I can get easily expansion equivalent to N+3.
Maybe your solutions (mainly A) was too old, or you messed up at exposure time.
Another thing, a higher temperature for expansion would have been recommended. I use it a 75º and if you use it at 78º you can get extreme contrasts (yep, I messed up and got eclipse viewing negatives)
Waste a few sheets and do some testing, or better yet do a full test program.
thanks for the trouble of a reply.
the negs may have been underexposed by about a stop and a half. I figured prolonged development would take care of that. Taking the pictures, I did what I had to do in terms of the weather and the moving ships. I was shooting with a 600 f9 Nikkor in foggy overcast at 1/125 f16. At least I have sharp negs to work with.
I am using the formulary mix so the proportions are right. My times for tri-x in sunlight at ei 160 is 6 min which is close to yours. the solutions were mixed about 2 weeks ago.
I'm beginning to think the problem is that there was nothing to expand in the scene. The 24 min negs have more film base + fog, but not much denser highlights. Heavy fog, overcast, with dark gray ships, painted to be hard to see. (given the weather, you'd think they'd paint them bright orange for the occasion!.
I have very little experience shooting "distant" subjects in the fog. thinking back every time I've gotten good expansion, it was a dull day but a closeup subject.
I'll do a test of a closer subject today and see if I get better expansion.
Donald, thanks for the Adams reference. I have some selenium, I'll give it a try.
Jorge, I'll also try some expansion tests at a higher temp.
And, perhaps, the pictures will look better printed.
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6.3 grams Sodium Carbonate (monohydrate) in 1 liter water, add 10ml solution "A", and off you go! That's the Sodium equivalent of 1:1:100. The Sodium Carbonate is easy to get as cleaning supplies (that's how I buy mine).
My last negs were developed in 4 weeks old sol. A, so it doesn't age too fast when stored properly. Given the light leaks in my darkroom I develop by inspection, so I have no idea about the times except that it was more than six minutes. The "Nameless Stream" in the critique gallery is from one of those. The shadows are very thin, but I didn't want the water to get too bright. SBR was about 3 stops.
-- Ole Tjugen, Luddite Elitist